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Understanding how neurovascular coupling changes during postnatal development

$2.3 million NINDS grant to aid interpreting fMRI signal in infants and children

Chris Spallino

November 28, 2017

Understanding how neurovascular coupling changes during postnatal development

UNIVERSITY PARK, Pa. — Penn State researchers have received funding from the National Institute of Neurological Disorders and Stroke to determine how the communication between neurons and blood vessels of the brain changes from postnatal development through adulthood, which would enable the use of hemodynamic imaging to study neural activity, plasticity, and neurodevelopmental disorders in infants, children and animals.

Patrick Drew, Huck Distinguished Associate Professor of Engineering Science and Mechanics, Neurosurgery and Biomedical Engineering, and Nanyin Zhang, professor of biomedical and electrical engineering, are co-principal investigators on a five-year, $2.3 million proposal titled “A Multimodal Approach to Understanding the Development of Neurovascular Coupling.”

Hemodynamic signals, the basis of functionality for functional magnetic resonance imaging (fMRI), are used to detect active areas in the brain relative to inactive areas. The signals allow researchers to noninvasively assay neural activity and can provide valuable insight into brain activity and cognitive function. However, it is not clearly understood how neural activity is related to changes in blood flow and oxygenation in the neonatal and juvenile brain.

Previous studies in anesthetized animals and sedated humans have come to conflicting results as to the sign and magnitude of neurovascular coupling, and this unresolved issue has stalled the use of hemodynamic imaging in infants and children.

“We can use fMRI in humans to visualize hemodynamic signals in the brain, but whether these signals mean the same thing in adults and children is not clear,” said Drew. “This work will use MRI, electrophysiological and optical techniques to understand what the neurons are doing as the brain develops, and how neural activity corresponds to the signals we see with fMRI.”

Using this multimodal approach, Drew and Zhang will elucidate the relationship of hemodynamic signals to neural activity from the levels of single blood vessels up to the whole brain, and determine how neurovascular coupling changes during postnatal development, how it impacts blood oxygen level-dependent fMRI signals, and how behavioral state can alter neurovascular coupling.

“fMRI is a powerful tool that has the potential to aid diagnosis and evaluate different treatment options for many brain development-related disorders,” said Zhang. “However, we need to know how to interpret fMRI signal in youth in terms of underlying neural activity before this capacity can be fully realized. The research proposed in this grant may help us achieve that goal.”

Drew and Zhang, along with Xiao Liu, assistant professor of biomedical engineering, have also received $3.7 million from the National Institutes of Health for a separate project to investigate the resting state of fMRI techniques and how they can help combat brain diseases.